Tricky-Ricky Posted June 11, 2008 Share Posted June 11, 2008 Here we go again, will put all in the one thread, first off i think i have fixed the oil feed leak, bar a very small amount from i think the feed pipe, however i took it out for a few short runs and here are my observations, first the smoke issue, i still seem to have some smoke on the over run, but not always, it doesn't smoke that i can see when i lift off after a boosted run, and i would expect it too then, but if run in traffic just cruising and lift off then quite often i get smoke, any ideas, my compression and leak-down test where all good! please don't tell me this turbo seals are leaking:( Next, i first ran it on the wast-gate spring, and it seems to be 0.5 bar which is fine by me as i only want to run maybe 1.0 bar, but i have tried auto and manual settings on my BC and if i set a target of 0.9 bar i get only 0-79 bar at best, maybe i just need to fiddle more but I'm used to this BC so ?? also not impressed with the amount of lag, despite winding up the gain, i thought a GT4088 could make 1.1 bar by 3,500RPM in best circumstances, but this seems to take ages well over 4,000RPM, waste-gate maybe? Any suggestions? Quote Link to comment Share on other sites More sharing options...
SteveR Posted June 11, 2008 Share Posted June 11, 2008 Blue smoke or black smoke? Quote Link to comment Share on other sites More sharing options...
JamieP Posted June 11, 2008 Share Posted June 11, 2008 Only thing i may be able to help with is the last question, what .AR do you have on the gt4088? in my experience the .96 gt4088 is very laggy, about 4000rpm for full boost in top but the .81 was making 1.2bar by 3300rpm in my car. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 Oh its oil alright, cant mistake the smell;) been thinking, has anyone had any issues with smoking, and cured it by restricting the oil to the turbo? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 Only thing i may be able to help with is the last question, what .AR do you have on the gt4088? in my experience the .96 gt4088 is very laggy, about 4000rpm for full boost in top but the .81 was making 1.2bar by 3300rpm in my car. Unfortunately its a .81 housing Jamie, thats why I'm worried and disappointed. Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 11, 2008 Share Posted June 11, 2008 How are you mapping it and what with? What ECU, injectors etc? Still the Emanage Ult? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 How are you mapping it and what with? What ECU, injectors etc? Still the Emanage Ult? Yes still with ultimate, and running 540 cc drop ins, its running a little on the rich side for safety until i get the boost stable, however none of that is going have that much bearing, i am still running my old hybrid ign timing map for off boost/closed loop, so its got a bit of advance in there;) wondering if i need to ramp it up some more? Quote Link to comment Share on other sites More sharing options...
kieren1234 Posted June 11, 2008 Share Posted June 11, 2008 What is the oil feed flange like. Does it have a small hole to restrict the oil going into the turbo. It may be that it cannot drain as quick as it feeds so is leaking elsewhere?? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 Flange has a maybe 4-5mm hole, but its not BB, so in theory shouldn't need one? and the return is -10 which i think is the recommended size? Quote Link to comment Share on other sites More sharing options...
RobSheffield Posted June 11, 2008 Share Posted June 11, 2008 This oil feed pipe leak then.... What oil pressure are you seeing? Measured where? What make is the oil feed and return kit? Does it still have ptfe on? What exhaust manifold are you using? Quote Link to comment Share on other sites More sharing options...
gaz1 Posted June 11, 2008 Share Posted June 11, 2008 have you checked condition of turbo before fitting, or is it a new one, if its laggier than the norm it could be fucked blades like mine was:( Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 This oil feed pipe leak then.... Oil leak pretty much cured apart from the feed pipe which is just getting oil build up after time. What oil pressure are you seeing? Measured where? oil pressure AFAK is what the rest of the system is seeing around 80-90 psi at over 3.500RPM measured at Lexus bolt. What make is the oil feed and return kit? No idea, but pics in the link I've posted. Does it still have ptfe on? No! locktite now. What exhaust manifold are you using? XS Power, checked for all the usual problems;) Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 OK its looking like i may have been unlucky and either bought a turbo with seal leaking, or the seal is being overwhelmed by oil pressure?? The turbo was supposed to have only done about 500mls according to Jezz who originally sold it to Migictorch (Jamie) who never fitted it, which i bought from him in good faith, as he did from Jezz, sale link here,http://www.mkivsupra.net/vbb/showthread.php?t=150056 I have now taken it off to reveal oil in the exhaust housing, and here are some pics of the exhaust turbine, and you can see a wet area , i have cleaned it a little, but it looks to me like its leaking, (only drove it for about twenty mls) So is it due to too much oil pressure, (should there be an additional restrictor??) or is my luck just shit! Quote Link to comment Share on other sites More sharing options...
kieren1234 Posted June 11, 2008 Share Posted June 11, 2008 Flange has a maybe 4-5mm hole, but its not BB, so in theory shouldn't need one? and the return is -10 which i think is the recommended size? 4 - 5mm?? Is that the hole size on the turbo OR the bolt on flange as most bolt on flanges will only have a pin (ish) sized hole so that the oil doesnt go in quicker than it can come out. Quote Link to comment Share on other sites More sharing options...
kieren1234 Posted June 11, 2008 Share Posted June 11, 2008 OK its looking like i may have been unlucky and either bought a turbo with seal leaking, or the seal is being overwhelmed by oil pressure?? The turbo was supposed to have only done about 500mls according to Jezz who originally sold it to Migictorch (Jamie) who never fitted it, which i bought from him in good faith, as he did from Jezz, sale link here,http://www.mkivsupra.net/vbb/showthread.php?t=150056 I have now taken it off to reveal oil in the exhaust housing, and here are some pics of the exhaust turbine, and you can see a wet area , i have cleaned it a little, but it looks to me like its leaking, (only drove it for about twenty mls) So is it due to too much oil pressure, (should there be an additional restrictor??) or is my luck just $#@!! http://i208.photobucket.com/albums/bb118/Tricky-Ricky13/001-2.jpg http://i208.photobucket.com/albums/bb118/Tricky-Ricky13/002-1.jpg Does not neccessarily mean the turbo seals have gone. There is definately too much oil pressure. This happened on an old turbo i had and the oil drain line wasnt getting rid of the oil quick enough, hense why the oil escaped elswhere into the exhaust housing (like mine did) and by god did it smell. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 I see what your saying but i was under the impression that if the turbo had plain floating bearings like the std ones, then the oil feed was just run on system pressure, as there is no restrictor in the std turbos, and it was BB cartridge type that need the oil pressure restricting, and turbo experts care to comment?? Quote Link to comment Share on other sites More sharing options...
Homer Posted June 11, 2008 Share Posted June 11, 2008 I see what your saying but i was under the impression that if the turbo had plain floating bearings like the std ones, then the oil feed was just run on system pressure, as there is no restrictor in the std turbos, and it was BB cartridge type that need the oil pressure restricting, and turbo experts care to comment?? Spot on, if it's pressure inside the cartridge thats causing the leak then the cartrisge is knackered anyway. The drain is gravity fed but as it's 10 times the area of the feed the oil pressure would have to be just enormous to cause a leak. Unfortunately, it looks like buggered turbo seals. It's a pretty crap turbo by all accounts, so might be best to get something a bit more beefy. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 11, 2008 Author Share Posted June 11, 2008 Been doing a little research, and it turns out quite a few people have had smoking problems similar to mine and cured it with the fitting of a restrictor, could be dodgy seal but its worth fitting one to find out, the only other option is to revert to my old turbos or scrape up the cash to fix this one, buying a new one is not an option:( Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 12, 2008 Author Share Posted June 12, 2008 Did a bit more searching, and turned up some interesting facts regarding the use of oil restrictors on plain bearing turbos, and even Garrett recommend the use of them if oil pressure is high, I'm awaiting contact regarding my query, but the general consensus is that even a plain bearing tubos will have oil pushed past the seals if the oil pressure is to high, ideal is 30- 40 psi any more and there is a risk of either seal failure or leakage, now i have an idle pressure of 25 psi min and my pressure will go up over the 90 psi mark at high RPM, and most of the tine its around 70 psi, so I'm looking into getting the right sized restrictor, and give it a try. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 12, 2008 Author Share Posted June 12, 2008 OK another update, after talking to some turbo specialists, it seems that a restrictor should in most cases not be used, however, it seems if the seal is not screwed (need to have that checked before verdict) it could be that high oil pressure coupled with low back pressure in the exhaust could combine to help the seal to leak a bit! confused? i am. So do i risk making a smaller restriction in the oil way and run the risk of screwing the bearings as well, or just bite the bullet and send the dam thing off to be checked, and max the credit card some more:( Anyway here is another interesting fact to add to the failing GT4088 mystery, the material that the exhaust turbine is made of is no different to all the other petrol use turbos, and the only explanation that i could glean for the destruction of the exhaust turbines that have been experienced is that the housing material is different and could distort and go oval thereby wearing the blades, but that doesn't explain the eroded look of the ones that have been shown. Quote Link to comment Share on other sites More sharing options...
bignum Posted June 12, 2008 Share Posted June 12, 2008 Its all good fun aint it mate. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted June 12, 2008 Author Share Posted June 12, 2008 Its all good fun aint it mate. I'm starting to reach the banging my head against the wall stage, mainly due to all the extra money that I'm having to spend, but don't have, looking at £200+ for a rebuild Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.